Not to worry, we've got 3219923903 and 9125204240. Let's get to adding them!

Step 1: We'll start by adding the digits 3 & 0 in column 1 and get 3.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

Step 3: We'll start by adding the digits 9 & 2 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 4 in column 4 and get 8.

Step 5: We'll start by adding the digits 2 & 0 in column 5 and get 2.

Step 6: We'll start by adding the digits 9 & 2 in column 6 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 7: We'll start by adding the digits 9 & 5 in column 7 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 8: We'll start by adding the digits 1 & 2 in column 8 and get 4.

Step 9: We'll start by adding the digits 2 & 1 in column 9 and get 3.

Step 10: We'll start by adding the digits 3 & 9 in column 10 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 3219923903 + 9125204240 = 12345128143.

